From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Chenguang Zhao <chenguang.zhao@linux.dev>
Cc: Aamir Ahmed <elb12345@hotmail.co.uk>,
netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] netfilter: conntrack_amanda: fix port value truncation
Date: Mon, 7 Sep 2026 18:37:43 +0200 [thread overview]
Message-ID: <ap7oV1cftWpjsBiJ@chamomile> (raw)
In-Reply-To: <214d51c6-a71b-4b93-8dd7-6bd1c02b4c3f@linux.dev>
On Mon, Sep 07, 2026 at 02:56:13PM +0800, Chenguang Zhao wrote:
>
> 在 2026/9/7 07:37, Aamir Ahmed 写道:
> > amanda_help() uses simple_strtoul() to parse the port number from
> > Amanda CONNECT replies, passing the result directly through htons()
> > into a __be16. simple_strtoul() returns unsigned long, so values
> > above 65535 are silently truncated by the implicit conversion to u16
> > inside htons().
> >
> > The existing check "port == 0 || len > 5" is insufficient: it
> > catches values that truncate to zero (e.g. 65536) and strings longer
> > than 5 digits, but misses values 65537-99999 whose u16 truncation is
> > non-zero. For example, port 65537 becomes port 1, creating a
> > conntrack expectation for an unintended port.
> >
> > Parse into an unsigned long and explicitly reject values above 65535
> > before the htons() conversion, mirroring the pattern used by the FTP
> > helper's get_port() and the recent IPVS FTP fix (commit
> > e625a9477d12).
Please, specify target tree. This must go to nf-next.
next prev parent reply other threads:[~2026-09-07 16:37 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-06 23:37 Aamir Ahmed
2026-09-07 6:56 ` Chenguang Zhao
2026-09-07 16:37 ` Pablo Neira Ayuso [this message]
2026-09-08 1:37 ` Aamir Ahmed
2026-09-07 8:33 ` Florian Westphal
2026-09-09 9:39 ` netdev-bot+sashiko
2026-09-09 12:14 ` Florian Westphal
2026-09-09 23:28 ` Aamir Ahmed
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